Background and objectives: Spontaneous remission (SR) in de novo myelodysplastic syndromes (MDS) is a rare event, which has been so far described only in children with monosomy 7. The phenomenon is extremely heterogeneous, perhaps depending on different pathogeneses of the disease.
Design and methods: We retrospectively evaluated the outcome of 564 consecutive adult patients with primary MDS diagnosed at our Institution in a 12-year period. SR was defined as an unexpected improvement lasting more than 1 year without concomitant treatments other than vitamins or low-dose steroids (in patients with platelets < 50 x 10(9)/L).
Results: Nine cases of SR were observed in 3 males and 6 females (median age 38.7 years). At diagnosis, all patients had Hb levels < 10 g/dL and 8/9 required packed red cell transfusions. The median time from diagnosis to SR was 18 months (range 4-46) and all patients had normalization of peripheral blood parameters: in 2 out of 3 patients with karyotypic abnormalities at onset, a cytogenetic remission was documented. The median duration of SR was 56 months; 5 patients are still in SR and 4 patients have relapsed (1 as MDS and 3 as acute myeloid leukemia).
Interpretation and conclusions: SR is a rare (less than 2% in our experience) but possible event also in adult MDS patients. It should be kept in mind in the evaluation of experimental treatments for MDS in which very low rates of complete responses are expected.